The call was made to Indigo's call centre at around 4 pm that a bomb has been placed in the Delhi-Kolkata flight (No: 6E203), which was to take off at around 4:30 pm, an airport official said.
The flight was actually to take off at 3:30 pm but was rescheduled because the airport was closed for about two hours as part of a security drill ahead of Independence Day celebrations.
Security personnel have cordoned off the plane and checks are on. There are 124 passengers and six crew on board.